1911 Encyclopædia Britannica/Galeopithecus
GALEOPITHECUS, the scientific designation of the Colugo (q.v.) or Cobego, commonly known as the flying-lemur, and alone representing the family Galeopithecidae. Much uncertainty has prevailed among naturalists as to the systematic position of this animal, or rather these animals (for there are two species); and while some have referred it to the lemurs, others have placed it with the bats, and others again among the Insectivora, as the representative of a special subordinal group, the Dermoptera. Dr H. C. Chapman, who has made a special study of the creature, writes, however, as follows: “It appears, at least in the judgment of the author, that Galeopithecus cannot be regarded as being either a lemur, or insectivore, or bat, but that it stands alone, the sole representative of an ancient group, Galeopithecidae, as Hyrax does of Hyracoidea. While Galeopithecus is but remotely related to the Lemuroidea and Insectivora, it is so closely related to Chiroptera, more particularly in regard to the structure of its patagium, brain, alimentary canal, genito-urinal apparatus, &c., that there can be but little doubt that the Chiroptera are the descendants of Galeopithecus, or, more probably, that both are the descendants of a Galeopithecus-like ancestor.” Without going quite so far as this, it may be definitely admitted that the colugo is entitled to represent an order by itself, the characters of which will be as follows: Herbivorous, climbing, unguiculate mammals, provided with a very extensive flying-membrane, and having the dental formula i. 2, c. 0, p. 3, m. 3, total 34. The lower incisors are directed forwards and have a comb-like structure of their crowns, while the outermost of these teeth and the canines are double-rooted, being in these respects, taken together, quite unlike those of all other mammals; the cheek-teeth have numerous sharp cusps; and there is the normal replacement of milk-molars by premolars. In the skull the orbit is surrounded by bone, and the tympanic has a bulla and an ossified external meatus. The ulna and fibula are to some extent inclined backwards; the carpus has a scapho-lunar; and the feet are five-toed. The hemispheres of the brain are short and but slightly convoluted; the stomach is simple; there is a large caecum; the testes are received into inguinal pouches; the uterus is two-horned; the placenta is discoidal; and there are two pairs of pectoral teats. A single offspring is produced at a birth.
|Feet of Philippine Colugo, or Flying-Lemur (Galeopithecus philippinensis).|
It will be obvious that if other representatives of the Dermoptera were discovered, some of these features might apply only to the family Galeopithecidae.
There are two species, Galeopithecus volans, ranging from Burma, Siam and the Malay Peninsula to Borneo, Sumatra and Java, and G. philippinensis of the Philippine group. The former, which is nearly 2 ft. in total length, is distinguished by its larger upper incisors, shorter ears and smaller skull. In both species not only are the long and slender limbs connected by a broad integumentary expansion extending outwards from the sides of the neck and body, but there is also a web between the fingers and toes as far as the base of the claws (fig.); and the hind-limbs are further connected by a similar expansion passing outwards along the back of the feet to the base of the claws, and, inwardly, involving the long tail to the tip, forming a true interfemoral membrane, as in bats. Besides differing from bats altogether in the form of the anterior limbs and of the double-rooted outer incisors and canines, Galeopithecus contrasts strongly with that order in the presence of a large sacculated caecum, and in the great length of the colon, which is so remarkably short in Chiroptera. From the lemurs, on the other hand, the form of the brain, the character of the teeth, the structure of the skull, and the deciduate discoidal placenta at once separate the group. (R. L.*)